I highly doubt that it's possible to have two hypervisors running at the same time, and I'm pretty sure that, knowing Microsoft, Sandbox will be running in the background for whoever is having the problem. Simplest solution? Check the list of running services .. there are 8+ Hyper-V on my system - all stopped.

Hi,I had the exact same error as reported in the original post, again after Windows 10 updated to 1903 build 18362.267 (without asking I might add)The difference may be that, seeing I had the update anyway, I might try the 'sandbox' - so it might have turned on hyper-v

Thanks for this helpful discussion. FYI, in my case the solution was the deactivation of the Windows features Hyper-V and Containers, which was enabled after the Win 10 1903 upgrade. All the other settings were still disabled. A de- and reinstallation of VB was not necessary (My VB version was 6.0.10).

My suggestion, why these feature were enabled after the upgrade - I tried some month ago Docker and switch back to VB.Therefore, I had to activate Hyper-V and deactivate it afterwards - see Stackoverflow - virtualbox Raw-mode is unavailable courtesy of Hyper-V windows 10. This was all done longtime ago before the Win 10 1903 upgrade and VB was running without problems again, but maybe not all feature changes by Docker were reset completely, which then let the Win10 upgrade decide to enable the above features.

If you had read the whole thing, you wouldn't be asking if it's a bug or not. Unless you want to call Hyper-V a bug, that's a stretch actually...

Do NOT send me Personal Messages (PMs) for troubleshooting, they are simply deleted.Do NOT reply with the "QUOTE" button, please use the "POST REPLY", at the bottom of the form.If you obfuscate any information requested, I will obfuscate my response. These are virtual UUIDs, not real ones.